Gaseous discharge tube detector circuits



Feb. 18, 1958 A. B. WIT ZEL ET AL 2,824,237

' GASEOUS DISCHARGE 'TUBE DETECTOR CIRCUITS Filed July 25, 1954 I 2 Sheets-Sheet 1 INVENTORJZ' finial; 5. 24/113 9! I BY ,F'mnk E. Trainer A TTOR/VEY Feb. 18, 1958 Filed July 23, 1954 METER JLAMPS PULSE AMPLITUDE VQLTS A. B. WITZEL ETAL GASEOUS DISCHARGE TUBE DETECTOR CIRCUITS 2 Sheets-Sheet 2 eo so 76o 740 750 VOLTS RADIATION TUBE ANopE INVEN TOR$'.

BY Ban]: E. Tmmar ATTORNEY United States Patent fifice 2,824,237. Patented Feb. 18, 1958 GASEOUS DISCHARGE TUBE DETECTOR CIRCUITS Anton B. Witze], Elmhurst, and Frank E. Trainor, North Lake City, 111., assignors to Admiral Corporation, Chicago, 11]., a corporation of Delaware Application July 23, 1954, Serial No. 445,374

19 Claims. (Cl. 25083.6)

ize gases is the characteristic most frequently used to detect their presence. One device for such detection is a self quenching radiation counter tube which is filled with a neon-halogen gas admixture at a low pressure. Across the two elements of the tube a voltage is impressed, whose magnitude is just below that necessary to ionize the gas molecules and cause conduction. When radiation is present in the vicinity of the tube, an incoming radiation particle will ionize some of the molecules, causing conduction between the elements. The current flow between elements of the tube which is the result of an ionization event is quenched by a small amount of halogen gas present within the glass envelope. More specifically, the halogen gas functions to prevent secondary electron emission from the cathode when the ions in the counter tube strike said cathode. Consequently, no new electrons are produced which could start a new cycle. However, immediately after the occurrence of ionization within the tube due to the radiation particle the space charge of the ion sheath developed therein will decrease the anode to cathode voltage across the tube so that a second radiation particle entering the counter tube will not produce a pulse. However, as the space charge moves toward the cathode the field will increase until, after a certain time interval has elapsed following the entering of the first particle into the counter tube, a second particle will produce a small, but measurable pulse. This certain elapsed time interval is known as the dead time.

The limits of usefulness for a radiation counter tube operating in the Geiger region of its characteristic, is fixed by the intrinsic dead time following a count, in which the tube is momentarily incapable of responding to ionizing events. As the radiation intensity approaches or exceeds this limiting condition, saturation results in a situation where the tube does not recover completely between successive discharges. This present invention provides a means for extending the upper limit level of operation for a tube of any given sensitive volume, by activating the tube for brief intervals as determined by the duration of an applied power pulse.

In order to achieve these ends, the radiation counter tube is driven into its over-voltage region for a statistical sampling pulse period, and the tube is made sensitive as a detector device only during the pulse duration. Accordingly, the activating pulse must be very short with respect to the dead time of the tube and its amplitude must be relatively high in order to drive the counter tube into the over-voltage region. The source of activating pulses in the present invention, is capable of developing a high voltage pulse of short duration and having a very short rise time from a relatively small power supply. The count rate response to ionizing radiation is sampled statistically, by being scaled down by the combination of pulse width and repetition rate. The maximum possible count rate is reached when, with the pulse period equal to the radiation counter tube dead time, each applied power pulse is associated with an external ionization event. By adjusting the pulse width the probability of a coincidence between it and an ionization event can be manipulated, thereby furnishing a means for controlling the maximum resolution of the instrument.

In accordance with the present invention, a portable radiation detector is provided, having a limited power, high voltage supply, a radiation detector tube means, a source of high voltage pulses, and an indicator. The power source supplies a constant D. C. voltage across the elements of the detector tube and the pulses are superimposed on the D. C. voltage. if a radiation pulse enters the detector tube at the time the high voltage pulse is present, the gas mixture in the tube ionizes and an output pulse is developed; it the two pulses do not occur simultaneously, the gas does not ionize sufiiciently to be detected by the indicator circuit. In effect, the pulse from the high voltage pulse source causes the radiation field to be statistically sampled, whereby increasing radiation intensity produces a higher output pulse rate, which is integrated in an indicating circuit to produce a meter reading.

The indicator circuit includes means for stabilizing the meter readings at low detector current output levels to compensate for varying supply voltages and variations in threshold voltages of the counter tube, wherein either variation would tend to produce a false indication of detection.

An object of the present invention is to provide a detector circuit for increasing the upper intensity limit of operation of a gaseous discharge counter detector tube.

Another object of the invention is the provision of a detector circuit operating from a limited power supply.

A further object of the invention is to provide a generator for sharp high voltage pulses having low power requirements.

Still another object is the provision of a stable detector circuit irrespective of wider tolerances in components and variations in supply voltage.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the annexed drawings, which illustrate a preferred embodiment, and wherein:

Fig. 1 shows a preferred embodiment in the form of a circuit diagram of the radiation detector of the invention.

Figs. 26 show typical characteristic curves of portions of the circuit and waveforms to facilitate a better understanding of the invention.

Referring now more particularly to Fig. l of the drawings, there is represented therein a circuit for a portable radiation detector unit, including an oscillator for generating pulses to drive a radiation counter tube into overvoltage conditions for the duration of the pulse, thereby sampling the radiation field. A radiation counter tube 10 and gaseous discharge tube 35) of the relaxation oscillator circuit are supplied by a limited power, high voltage supply, regulated by a voltage stabilizing circuit.

Referring more particularly to the power supply circuit, there is shown in Fig. 1 dry cells 12 connected in series with the primary winding of transformer 14 and vibrator 15 through the switch arm 13. The secondary of transformer 14 is connected from its positive terminal to rectifier 16, to supply a direct current high voltage to the stabilizing circuit, wherein filter condenser 17 is connected across the secondary winding of transformer 14 and rectifier 16.

A filter comprising resistors 11?, 2 condenser 25, and gaseous voltage regulator tube 2%, form a filter circuit to prevent pulses from the relaxation oscillator from affecting the D. C. regulated supply and to furnish an adjustable anode voltage for counter tube 10. Voltage regulator tube 19 is connected across the rectified output of the transformer 14 regulating the voltage to a level slightly higher than the voltage level of regulator tube 20. Tubes 19 and 20 are high impedance, low current, voltage regulator tubes for stabilizing voltages at currents below 1 milliampere, and above the voltage limits of conventional glow tube regulators. A variable tap is provided on resistor 24 for regulating the voltage supplied to the anode of the counter tube through resistor 26. The lower level of voltage across the voltage regulator tube is supplied to the circuit of the relaxation oscillator through variable charging resistor 27 and resistor 28.

The pulse generator circuit includes gaseous discharge tube 30, load resistor 32, charging resistors 27, 28, and charging capacitor 33; capacitor 33 is connected across the generator tube and resistor 32. A further capacitor 34 is connected across resistor 32 to modify the output power pulse waveform from the generator circuit. The anode of the counter tube 10, which is supplied by a relatively constant source of D. C. voltage through vari able resistor 24 and resistor 26, is coupled to the output of the relaxation oscillator circuit through coupling capacitor 35, whereby the power pulses are superimposed upon the D. C. voltage supply and applied to the anode of the counter tube 19, for a purpose which will be explained further hereinafter.

The current output of the counter tube 10 is coupled directly to the indicator circuit, including transformer 37, rectifier 38 and ammeter 39. The secondary winding of transformer 37 is connected in series with rectifier 38 to ammeter 39, in parallel with filter condenser 40. Rectifier 38, along with condenser 40, provide a suitable D. C. current for stable meter deflection from the coincidental signal current pulses from the radiation counter tube.

A two position switch 42 is shown in the metering position connecting the meter to the output of the detector circuit at terminal 43. Terminal 44 is connected to the positive terminal of batteries 12 through current limiting resistor 52 to provide a supply source voltage checking circuit.

The counter tube 10, shown in Fig. 1, may be of the self-quenching type wherein a quantity of halogen gas is enclosed within the tube envelope and which extinguishes after a radiation pulse is formed at the anode of the tube. The pulse height vs. overvoltage operating characteristic should be controllable for regulating the degenerative effect in the output for reason to be set forth hereafter.

Fig. 2 shows typical characteristic curves of two gaseous radiation counter tubes of the type described which will vary in threshold voltage AV, due to tolerances in manufacture or drift due to age. The threshold voltage V is the voltage which, when applied to the anode of the tube, will cause the tube to conduct sufiiciently to produce a specified current when a radiation particle collides with a molecule of gas in the envelope of the tube, thereby causing ionization. Threshold voltage V may vary in either direction due to age, that is, the threshold voltage may increase or decrease as a result of deterioration of the tube, depending upon the type of chemical change which occurs within the glass envelope. V,, which is equal to the threshold voltage V plus a certain amount of overvoltage, indicates the voltage which is applied to the anode of the radiation counter tube in normal operation. The tube 1% will conduct as a result of ionization due to receipt of a radiation particle at the voltage V, applied to the anode from the power supply circuit, but the resulting current output will be below the minimum required to produce a meter deflection.

Fig. 3 shows a typical characteristic curve 48 of the gaseous generator tube 30. Generator tube 36 is of the corona voltage regulator tube type, having a high ionization potential E and having little or no corona discharge region when connected in reverse. The voltage is raised on one element of the tube to a potential E wherein the tube immediately goes into a glow discharge. This characteristic is shown in Fig. 3, wherein the tube voltage E is built up to the ignition voltage E, at which point the tube conducts and the voltage E drops to voltage E due to the change in the tubes impedance during ionization. This results in a pulse voltage approximately equal to E,E appearing across resistor 32 and therefore upon the anode of the gaseous counter tube 10.

The corona discharge tube is used primarily herein for voltage stabilization, when the tube elements were modified to eliminate the corona region, however, the tube was found suitable in an oscillator circuit for high voltage pulse of very short duration. As seen from Fig. 3, the voltage will build up to a high voltage or ionization potential E, at which point the tube immediately goes in glow discharge. The impedance of the tube drops, placing the voltage E,E across the load resistor 32 to develop sharp generator output pulse which is superimposed on the counter tube anode voltage.

The corona tube may be modified to fulfill the requirements of the pulse generator circuit by varying the ratio of the coaxial cylinder radii or the ratio of the anode radius R,, to the cathode radius R (R /R As the ratio of the coaxial cylinders is increased, the corona region decreases until the corona region disappears (radii ratio .37) and the discharge goes upon ionization directly into a glow discharge. The ionization voltage varies with distance between electrodes, relative size of the electrodes and the gas mixture inside the glass envelope of the tube.

In the circuit of Fig. 1, there is shown the gas discharge tube 30 having no corona characteristic and ionizing at approximately 400 volts (E Since the characteristic curve (Fig. 3) shows a sudden and substantial decrease in voltage across the tube 30 after ionization with practically no increase in current, the dry cell supply source 12 is capable of supplying sufiicient current for developing the sharp pulse 31. Further, corona tube 30 has no heater filament wherein a further current drain on the source 12 would make operation on a limited power source impractical, if not impossible.

The condenser charging current flowing through the generator circuit charging resistors 27 and 28, results in a slope of condenser voltage vs. time in the vicinity of ionization voltage such that the apparent supply voltage to the entire oscillator circuit is reduced. Under these conditions this slope charging is small, and minor changes in any factor affecting the potential of the initiation of glow will cause a relatively great change in pulse rate.

Fig. 4 discloses a typical response curve for meter defiection vs. counter tube anode voltage V in a constant radiation field. The area of stable operation is found on the relatively flat portion of the curve between V and V eliminating erroneous indications on the meter 39 due to variations in threshold voltage of the counter tube V or variations in supply voltage. The anode voltage in the counter tube is adjusted to an operating point 50 on the characteristic curve 49 by adjusting the variable resistor 24 to give an optimum reading.

The stable region of the curve (Fig. 4), V V allows for a deviation approximately 20 volts in either direction of the anode supply voltage for counter tube 10 without decalibration of the meter 39. This tolerance is necessary, as stated above, in order to provide for variations in supply voltage, operating characteristics of .the gaseous pulse tubes 30, and corona regulator tubes 19, 20, and threshold variations :of the radiation detector tube 10.

The stable region of the detector current output V V 'is obtained by a heavily over-damped transformer 37 for matchingthe outputimpedance of the detector counter tube '10 wherein the leakage reactance and distributed capacitance is conducive to ringing in the output circuit. Depending on the coincidence time of the radiation pulse and the generator pulse, the integrated current from the periodic damping ringing circuit changes.

The degenerative elfect in the detector circuit is attributed to the combined influence of the generator pulse coupling capacitor 35 and the transformer input impedance. The input impedance of transformer 37 is such that a coincidental ionization event and generator pulse results is induced voltage which remains across the primary of the transformer and which can hold the tube voltage below the operating point V,, (Fig. 2) for several microseconds. The capacitor 35 acting as a reservoir is momentarily discharged through the counter tube circuit during coincidental ionization events or radiation pulse and generator pulses, so that the counter tube anode voltage at the end of ionization is below its quiescent value for a period of time designated by the time constant of resistor 26, the right hand portion of resistor 24, resistor 13, and capacitor 35. Further, it has been determined empirically that the magnitude of the degeneration is controlled by the slope of the radiation counter tube characteristic (Fig. 6).

In operation, the anode of the counter tube It is supplied with a 13+ voltage from the voltage-stabilizing circuit, as adjusted by the tap on potentiometer 2d. Resistor 24 adjusts the voltage to the operating point 56 above the threshold voltage V of the counter tube 10.

The power supply, shown in Fig. 1, has a voltage source 12, which is connected to the vibrator 15 by a single pole switch 13 for supplying the primary of transformer 14. The pulsating current produced by the vibrator 15 produces a high voltage in the secondary of transformer 14, according to the ratio of primary to secondary turns. The high voltage is rectified and filtered through rectifier 16 and capacitor 17, for application across the voltage regulator tube 1.9. A second regulator tube 20 stabilizes the voltage at a slightly lower level than regulator tube 19. This voltage is applied through charging resistors 27 and 23 to the generator circuit, comprising tube 39, capacitor 33, and load resistor 32. As shown in Fig. 3, the voltage builds up on condenser 33 to the ionizing voltage of tube 30, whereupon tube 30 conducts, developing a pulse 31 across the load resistor 32. Capacitor 34 is shunted across resistor 32 for controlling the waveform of pulse 31 across resistor 32, i. e., decreasing the height and increasing the width with increased capacitance. Pulse 31, shown in Fig. 5, has a rise time of approximately .2 /1.SC., decreasing from peak voltage exponentially with time and a duration width of approximately 15 ,usec. The generator pulse is coupled to the anode of counter tube 10, adding to the D. C. level. If a radiation pulse enters the counter tube at the time the generator tube pulse is present at the anode, the gas mixture ionizes and output pulse is developed, if the two pulses do not occur simultaneously, the gas mixture of the counter tube does not ionize sufiiciently to cause meter deflection. Thus in efifect, the pulse from the generator causes the radiation field to be sampled.

The outut pulses from the counter tube are coupled to the transformer circuit via line 36 developing a current in theprimary winding of transformer 37. The signal current developed in the secondary of transformer 37 is rectified and then filtered by condenser 40 and added to the D. C. current from the lower end of the transformer primary. The meter 39 is coupled to the output signal current at terminal 43 through switch 42, and is calibrated appropriately for reading the intensity of the radiation field, according to the magnitude of the integrated signal current.

Transformer 37, being slightly over-damped, extends the duration of the input exciting pulses so that a limit is placed upon the number of generator pulses which can be applied to the radiation counter tube. This period would allow a generator frequency of 2,000 C. P. S., but due to the limited power supply a power pulse frequency of 5004500 cycles per second was found optimum and no advanta e was found in higher generator pulse frequency for indication purposes.

The magnitude of the signal current will vary depending upon the time of occurrence of the radiation pulse relative to the beginning of the generator pulse within its time period, i. e., the closer in time the radiation pulse occurs relative to the initiation of the generator pulse, the greater will be the amplitude of the signal pulse delivered to the transformer 37. The amplitude of the signal current is shown in Fig. 5, where the voltage induced in the secondary of transformer 37 in response to the signal currents has been indicated.

Since the output of the counter tube, and consequently, the meter reading, varies according to the regulated supply voltage, accurate readings canont be obtained over the voltage variation tolerance unless the supply voltage source 12. has a voltage above a predetermined mini mum. A meter checking circuit is found in Fig. l, wherein switch 42, at position 44, connects the meter 39 across the dry cells 12 through resistor $2, whereby their condition may be checked.

Although the circuit is not limited to specific values, in the detectors actually constructed the following values were used for the components in reducing the invention to practice:

Condenser 4'1 500 ,ufarads. Condenser 35 .Ol MfaIfldS. Condensers 17 and 25 .005 ,ufarads. Condenser 33 250 ufarads. Condenser 34 20 unfarads. Resistor 32 20 K.

Resistor 27 10 meg. Resistor 26 1.1 meg. Resistor 23 1.1 meg. Resistor 24 1.5 meg. Resistor l8 3.3 meg. Resistor 52 10 K.

Resistor 28 20 meg.

Tube 19 CK1037. Tube 29 VXR-600. Tube 30 EP92 or CKlO37 reversed. Meter 39 Microammeter.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as set forth in the appended claims.

We claim:

1. A system for compensating for variations in electronic discharge device operating characteristics or variations in supply voltage in a detector circuit, an electronic discharge detector device having at least two electrodes comprising, a source of supply voltage connected to a first electrode of said device, and a source of voltage pulses, circuit means for coupling said source of pulses to said first electrode, a damped matching impedance circuit connected to the output of said device having a reactance conducive to ringing in response to the output signal current of said device whereby a degenerative effect is produced in the detector circuit stabilizing the output signal thereby compensating for variations in supply voltage and electron discharge device characteristics.

2. A. system for compensating for variations in electronic discharge device operating characteristics or variations in supply voltage in a detector circuit comprising;

an electronic discharge detector device having at least two electrodes, a source of supply voltage connected to a first electrode of said device, and a source of voltage pulses, circuit means including a capacitor for coupling said source of pulses to said first electrode, a damped matching impedance circuit connected to the output of said device having a reactance conducive to oscillation in response to the output signal current of said device whereby a degenerative effect is produced in the detec- 7 tor circuit stabilizing the;output signal to compensatefor variations in supply voltage and electron discharge device characteristics.

3. A system for compensating for variations in electronic discharge device operating characteristics or variations in supply voltage in a detector circuit, an electronic discharge detector device having at least two electrodes, a source of supply voltage connected to a first electrode of said device, and a source of voltage pulses, circuit means including a capacitor for coupling said source of pulses to said first electrode, an over-damped matching impedance circuit connected directly to the output of said device having a reactance conducive to ringing in response to the output signal current of said device Whereby a degenerative effect is produced in the detector circuit stabilizing the output signal to compensate for variations in supply voltage and electron discharge device characteristics.

4. A system for compensating for variations in electronic discharge device operating characteristics and variations in supply voltage in a radiation counter detector circuit, a gaseous discharge radiation counter detector device having at least two electrodes, a source of supply voltage connected to a first electrode of said device, and a source of voltage pulses, circuit means including a capacitor for coupling said source of pulses to said first electrode, an over-damped matching impedance circuit connected directly to a second output terminal of said device having a reactance conducive to oscillation in response to the output'signal current of said device whereby a degenerative effect is produced in the detector circuit stabilizing the output signal to compensate for variations in supply voltage andelectron discharge device characteristics.

5. A system for increasing the intensity'limit of operation of a radiation detector circuit of any given-sensitive volume and the stability thereof for'variations in supply voltage, a gaseous discharge radiation detector device having a limited power supply subject to variations in voltage, means for generating sharp high amplitude pulses, circuit means for superimposing said pulses on the supply voltage for said device, a supply circuit for applying said supply voltage and pulses on said device for statistically sampling the radiation ionization current condition of said device, and an over-damped matching impedance circuit having a reactance conducive to ringing connected to the output of said device for producing a degenerative effect in the device to compensate for variation in supply voltage.

6. A system for increasing radiation intensity limit of operation of a radiation detector circuit of any given sensitive volume and the stability thereof for variations in supply voltage, a radiation counter gaseous discharge device having a limited power supply subject to variations in voltage, a low current, high amplitude pulse generator circuit for generating sharp high amplitude pulses comprising a gaseous discharge device having a high ignition voltage discharging in a low impedance glow region of operation upon ignition, circuit means for superimposing said pulses on the supply voltage for said device, a supply circuit for applying said supply voltage and pulses on said device for statistically sampling the radiation ionization condition of said device, and an over-damped matching impedance circuit having a reactance conducive to oscillation connected to the output of said device for producing a degenerative effect in the device to compensate for variations in supply voltage.

7. The method of increasing the stability and intensity limit of a detector circuit having a pulse operated gaseous discharge detector and a power supply subject to varia tions in output voltage comprising the following steps: applying a supply voltage subject to variation to the detector, superimposing sharp high amplitude pulses on said voltage, matching the output impedance of. said detector.

8 by anover-damped. matching impedance circuit having a reactance conducive tov ringing. whereby a degenerative effect is'produced .in thedetectorcircuit.

8. The method of increasing the stability and intensity limit of a detector circuit having a statistical pulse sampled gaseous radiation counter tube detector and a power supply subject to variations in output voltage comprising the. following steps: applying a supply voltage subject to variation to the. detector, superimposing sharp high amplitude pulses of approximately 15 p.566. duration and 209 volts amplitude on said voltage, matching the output impedance of said detector by an over-damped matching impedance circuit having a reactance conducive to oscillation whereby a degenerative effect is produced in the detector circuit, and controlling the output level and extent of stabilization byvarying the slope of the pulse voltage amplitude vs. supply voltage operating characteristic of the detector.

9. The method of increasing the stability of a detector circuit having a gaseous discharge detector and a power supply subject to variation in output voltage comprising the following steps: matching the output impedance of the detector by a damped matching impedance having a leakage reactance and distributed capacitance conducive to ringing in the matching impedance producing a degenerative effect in the detector circuit thereby stabilizing the output current of the detector in the low current region, and controlling the detector output current operating characteristic with increased supply voltage to vary the amount of degeneration and extent of said low current region whereby the magnitude of the variations in power supply are accordingly within the extent and level of degenerative stabilization.

10. The method of increasing the stability of a detector circuit having a gaseous discharge detector subject to variation in threshold voltage and a power supply subject to variation in output voltage comprising the following steps: matching'the output impedance of the detector by an over-damped matching impedance having a leakage reactance and distributed capacitance conducive to ringing in the matching impedance, producing a degenerative effect in the detector circuit thereby stabilizing the output current of the detector in the. low current region, and controlling the detector output current operating characteristic with increased supply voltage to vary the amount of degeneration and extent of said low current region whereby the magnitude of the variations in threshold voltage and in power supply are accordingly within the extent and level of degenerative stabilization.

11. The method of increasing the stability of a radiation detector circuit having a gaseous radiation counter tube detector and a power supply subject to variation in output voltage comprising the following steps: statistically sampling the detector tube condition by superimposing sharp high amplitude pulses on the supply voltage, matching the output impedance of the detector by an overdamped matching impedance having a leakage reactance and distributed capacitance conducive to ringing in the matching impedance producing a degenerative effect in the detector circuit thereby stabilizing the output current of the detector in the low current region, and controlling the detector output current operating characteristic with increased supply voltageto vary the amount of degeneration and extent of said low current region whereby the magnitude of the variations in powersupply are accordingly within the extent and level of degenerative stabilization.

12. An oscillator for generating sharp pulses of high amplitude from a limited dry cell power source comprising: a gaseous discharge device having coaxial cylindrical electrodes including an anode and a cathode, the ratio of the radius of said anode to the radius of said cathode being in a range of values extendingfrom about'.37 upwards whereby-the device has a.high ignition voltage E and discharges in the low impedance glow region of operation upon ignition and whereby the said low impedance glow region extends substantially to an extinction potential E a load impedance connected to the output of said device and a capacitance connected across said device and said load impedance, means for charging said capacitance to the ignition voitage E, of said device at a predetermined rate, said device being responsive to said voltage to discharge in the low impedance glow region of operation and thereby develop a sharp high amplitude voltage pulse across said output load impedance.

13. An oscillator for generating sharp pulses of high amplitude from a limited power source comprising: a gaseous discharge device having coaxial cylindrical electrodes including an anode and a cathode, the ratio of the radius of said anode to the radius or" said cathode being about .37 whereby the device has a high ignition voltage E and discharges in the low impedance glow region of operation upon ignition and whereby said low impedance glow region extends substantially to an extinction potential E a load impedance connected to the output of said device and a capacitance connected across said device and said impedance, means including a limited power high voltage source for charging said capacitance to the ignition voltage E, of the device at a predetermined rate, said device being responsive to said voltage E to discharge in the low impedance glow region of operation and thereby develop a sharp high amplitude voltage pulse across said output load impedance.

14. An ionizing radiation detector circuit including a radiation detector tube having at least first and second electrodes; a supply potential, subject to variations in voltage, connected to said first electrode; a circuit for generating pulses and superimposing said pulses on said supply potential at said first electrode, said tube being responsive to radiation events occurring during the pulses to produce an output signal, said tube being further responsive to variations in said supply potential to vary the amplitude of the output signal, and circuit means connected to the output of said detector tube for producing degeneration in said detector tube proportional to the amplitude of said output signal.

15. An ionizing radiation detector circuit including a radiation detector tube, varying in threshold voltage, having at least first and second electrodes, a supply potentral subject to variations in voltage connected to said first electrode and a circuit for generating pulses and superimposing said pulses on said supply potential at said first electrode, said tube being responsive to said varlations in voltage to vary the amplitude of the output signal, circuit means connected to the output of said I detector tube for producing degeneration in said detector tube proportional to the amplitude of said output signal, whereby the variations in amplitude of the output signal due to supply voltage variations are offset.

16. An ionizing radiation detector circuit including a radiation detector tube having at least an anode and cathode; a supply potential, subject to voltage variations, connected to said anode; and a power pulse source; circuit means connecting said source to said anode superimposing said pulses on said supply potential, said tube being responsive to radiations coinciding with said power pulses to produce outputsignal pulses and responsive to variations in supply voltage to vary the amplitude of said signal pulses, a compensating circuit connected to an output electrode of said tube, said compensating circuit including an over-damped output impedance responsive to said signal pulses producing oscillations of at least one cycle, wherein each half cycle is of substantially longer time duration than said signal pulse, a unidirectional impedance, circuit means connecting said unidirectional impednnce to said output impedance for conducting on the negative half cycle, the positive half cycle applied to the output electrode effectively decreasing the voltage across said anode and output electrode proportional to the amplitude or said oscillations, said tube being responsive to said positive half cycles of said oscillation during the time period exceeding a predetermined amplitude to cut oil said tube and decrease the amplitude of said signal pulses during the remaining time period of said positive half cycle.

17. An ironizing radiation detector circuit including a radiation detector tube having at least an anode and cathode; a supply potential, subject to voltage variations, connected to said anode; and a power pulse source; circuit means connecting said source to said anode superimposing said pulses on said supply potential, said tube be ing responsive to radiations coinciding with said power pulses to produce output signal pulses and responsive to variations in supply voltage to vary the amplitude of said signal pulses, a compensating circuit connected to an output electrode of said tube, said compensating circuit including an over-damped output transformer responsive to said signal pulses producing oscillations of at least one cycle, wherein each half cycle is of substantially longer time duration than said signal pulse, a unidirectional impedance, circuit means connecting said unidirectional impedance to said output transformer for conducting on the negative half cycle, the positive half cycle applied to the output electrode effectively decreasing the voltage across said anode and output electrode proportional to the amplitude of said oscillation, said tube being responsive to said positive half cycles of said oscillation during the time period exceeding a predetermined amplitude to cut off said tube and decrease the amplitude of said signal pulses during the remaining time period of said positive half cycle.

18. An ionizing radiation detector circuit including a radiation detector tube having at least an anode and cathode; a supply potential, subject to voltage variations, connected to said anode; and a power pulse source; circuit means including impedance connecting said source to said anode, a pulse coupling circuit including a capacitor connecting said pulse source to said anode, superimposing said pulses on said supply potential, said tube being responsive to radiations coinciding with said power pulses to discharge and produce output signal pulses and responsive to variations in supply voltage to vary the amplitude of said signal pulses, said capacitor discharging with said tube lowering the anode potential of said tube below its operating voltage level for a time period determined by the time constant of said impedance and capacitor, a compensating circuit connected to an output elec trode of said tube, said compensating circuit including an over-damped output transformer responsive to said signal pulses producing oscillations of at least one cycle, wherein each half cycle is of substantially longer time duration than said signal pulse, a unidirectional impedance, circuit means connecting said unidirectional impedance to said output transformer for conducting on the negative half cycle, the positive half cycle applied to the output electrode effectively decreasing the voltage across said anode and output electrode proportional to the amplitude of said oscillations, said tube being responsive to said positive half cycles of said oscillation during the time period exceeding a predetermined amplitude to cut off said tube and decrease the amplitude of said signal pulses during the remaining time period of said positive half cycle.

19. An ironizing radiation detector circuit including a radiation detector tube varying threshold voltage having at least an anode and cathode; a supply potential, subject to voltage variations, connected to said anode; and a power pulse source; circuit means connecting said source to said anode superimposing said pulses on said supply potential, said tube being responsive to radiations coinciding with said power pulses to produce output signal pulses and responsive to variations in supply voltage to vary the amplitude of said signal pulses, a compensating circuit for said variations connected to an output electrode of said tube, said compensating circuit includ ing an over-damped output'impedance responsive to said signal pulses producing oscillationsof at leastone cycle; whereineachhalfcycle is of substantially longer' pedance to said output impedance for conducting on the negative half cycle, the positive half cycle" applied to the output electrode eifectively decreasingthe voltage across said anode and output electrode proportional to the amplitude of said oscillations; said tube-beingresponsive to said positive half cycles of said oscillationduring the time period exceeding 'a predetermined amplitude to" cut off said'tube and decrease the amplitude of '12 said signal pulses during the remaining time period of said positive half cycle, whereby the output of said circuitfis' substantially constant over the desired range of operating conditions of said tube, and means connected to-theoutput of said circuit for indicating'the signal output=of said circuit.

References Cited in the file of this patent UNITED STATES PATENTS 2,592,445 Groth Apr; 8, 1952 2,620,446 Le Vine et a1. Dec. 2, 1952 2,682,001 Duffy June 22, 1954 

